Machine for making cutters



(No Model.) 5. She etsSheet 1.

. W. D. MARKS.

MACHINE FOR MAKING CUTTERS.

Patented Nov. 23, 1886.

INVENTOR WITNESSES:

@wM/W (No Model.) 5 Sheets-Sheet 2.

w. D. MARKS.

MACHINE FOR MAKING GUTTERS No. 353,034. 7 Patented Nov. 23, 1886.

WITNESSES: INVENTOR wM,z@.-ZW/

N. PETERS, Phnlq-Eilhngmpher. Wmhingion. n. a

5 Sheets-Sheet 3.

(No Model.)

W. D. MARKS.

MACHINE FOR MAKING OUTTERS.

Patented Nov; 23, 1886 W'iTNESSES:

N. PUEBS Fholo-hlhognphur. wlshinglom D c.

5Sheets-Sheet 4.

(No Model.)

W. D. MARKS.

MACHINE FOR MAKING UUT'I 'ERS.

No. 353,034. Patented Nov. 23, 1886.

WITNESSES: INVENTOR @MMM QM J M u. wanna vhmu-umn n m wmingmv'. n. c.

5 Shets-Sheet 5.

(No Model.)

W. D. MARKS. MAGHINE FOR MAKING GUTTERS.

Patented Nov. 23. 1886.

INVENTOR WITNESSES:

u. PETERS. Pimlnnllliwgraphcr. Wznhingwn. D. C.

. 'NITED ST TES W'ILLIAMD. MARKS, OF PHILADELPHIA, PENNSYLVANIA.

MACHINE FIOR'MAKING CUTTERS.

$PECIPICATION forming part of Letters Patent No. 353,034, dated November 23, 1886.

7 Application filed May 29, less. Serial No. 203,595. (No model.)

' citizen of the United States, and a resident of the city and county of Philadelphia, and State of Pennsylvania, have invented a certain new and useful Machine for Making Mathematically-True Epicycloidal'Cutters by Means of a,-

Point-Tool, of which the following is a specification.

The object of my invention, which I call an Epicycloidal-Cutter Machine, is to originate mathematically-true cutters for cutting the teeth of gear-wheels by means of a point-tool. The mechanism will so guide the point of the tool as to cut the faces of the cutters teeth to a truly hypocycloidal form, and the flanks of the cuttcrs teeth to a trulyepicycloidal form, so that the cutting of the solid rim ofa blank wheel by one of these cutters will leave the teeth of the wheel with epicycloidal faces and hypocycloidal flanks.

This machine is particularly intended to evade all preliminary processes, such as the making of templets and the subsequent direct or pantographic transfer of their shapes, or the use of tools formed of an epicyeloidal shape on the cutting-edges. The point of the cutting-tool, when the machine is adjusted, will describe successively the hypo and epi cycloidal curves required, and will pass from one curve to the other without changing the grip on the tool at the point where the hypocycloid merges into the epicycloid, and therefore without showing anyjog in the shape of the cutter being formed. The center line of the tool-shank also will always be normal to -the curves being cut. It is the fact that this machine will cause the .points of the tool to originate and cut the mathematically-exact curves of the teeth of wheels for any describing-circle, any pitch-circle, and any number of teeth within limits of the size of the machine which renders it particularly useful,

and in which it is believed to differ in principle and action from all machines heretofore devised for the making of epicyeloidal cutters for the teeth of wheels.

In the accompanying drawings, forming part of this specification, and in which similar letters of reference indicate similar parts throughout the several views, Figure 1 is a diagram explaining the mathematical theory on which the construction of the machine is based; Fig. 2, a top view of the machine; Fig. 3, a side view, partly in section; Fig. 4, a rear View of the machine; Fig. 5, a partial front view with the standard forcenter of main ra- -line 1 2; Fig.- 8, a section of main radius-bar,

Fig. 2, on line 3 4; Fig. 9, a half-section of a false eccentric mandrel to be used when the pawls do not engage the teeth of the cutter itself; Fig. 10, a partial front view of false eccentric mandrel; Fig. 11, a side view of the cutter, supposed to be placed on an eccentric mandrel, showing position of pawls used to give it an intermittent rotary motion; and Fig. 12 is a side View of eccentric mandrel with half section of cutter in position, the pawls not being shown.

As this machine is believed to be entirely novel in its construction,it will be necessary to preface its detailed description by an explana tion of its mathematical theory.

According to the plan sometimes pursued by mechanics, a circular templet of the pitch-radius of the wheel to have its teeth formed is cut out. (Thisis represented in Fig. l by the pitch-circle,whose center is 0.) A describingcircle is then cutout, and a marking-point being fixed on its perimeter it is rolled on the outside and the inside of the pitch-circle, so as to form, by means of the point, the epicyeloidal, face and the hypocycloidal flank of the tooth desired. This describing-circle is represented in its various positions by the circles E E and H H If, now, we roll the describing-circle E upon the outside of the pitch-circle C, so that the marking-point P takes, finally, the position 1?, the point will have marked in its progress the epicycloid P 1 Then, placing the describing-circle H insideof the pitch-circle O, with the marking-point at P, if we roll Y the describingcircle to the position Hthe point will have marked the hypocycloid P P, and we have one side of an epicyeloidal tooth, P P P.

It will be observed, however, that if we take a radial bar, 0 R and pivot to it another radial bar, E P and cause bar 0 R to move through the angle R O Rflwhile bar E 1" moves through angle 0 E l? with a constant velocity ratio to it, we tracethe epicycloid P P; also, if we take a radial bar, 0 R, and pivot to it the radial bar H P, and cause bar C R to move through the angle R 0 R while bar H P with scribing-circle E", we have the following pro portion: G G E G 2: angle P -E G angle Gr 0 P; but as the radii of the pitch and describing circles are proportional to the assumed number of teeth on thecircles, we can say, by the rule of three, as is the number of teeth in the wheel desired to the number of teeth in the describing-circle, so is the angle G E P", which the describing radiusbar E P forms with the main radius-bar C R", to the angle R 0 R which the main radius-bar O R forms with its normal position G R".

.According to W'illiss system, the number of teeth assumed in the describing-circle would always besix, and according to the system most used in the United States the number of teeth assumed in the describingcircle would always beseven and a half. The construction of the machine, however, does not limit it to any fixed number of assumed teeth for the describing-circle, as will presently be seen from the detailed description, as well as how the relative angular positions of. the main radiussented in its consecutive positions by the lines T B T B T B", Fig. 1. The shank I of the point-tool P, Figs. 3 and 5, is always fixed parallel to the upper part, B, of the tool-bar T, Figs. 2, 3, and 5.

\Vhile there is but one main radius-bar, O B, Fig. 1, there are two describing radius-bars, E S and H P, one of which is fixed to the tool-bar at its end P, and the end S of the other describing radius-bar,ES,is free to slide along the length of tool-bar T B. When one of these describing-bars, as H P, is fixed to the tool-bar T B at P, the end of the other, as S, is free to slide along tool-bar T B lengthwise. From the direction of the arrows it will be seen that as bar 0 R moves along, carrying with it the centers of the describing radius-bars H and E, the two describing radiusbars H P and E S close in upon the main radiusbars from opposite directions with equal angles, and that while the point P,at the pivoted junction of the tool-bar T B and the describing radius-bar H P, is forcing the point P of the tool to trace a hypocycloid, P P, the end S of the describing radius-bar E S holds the tool-bar in a normal direction to the hypocycloid P P,because the angles G E S and P H G are always equal, and therefore the toolbar T B crosses the pitch-circle at the point of contact of the assumed pitch-circles E and H and describingcircle 0. When in the progress of the main radiusbar C It in the direction of the arrow it reaches the position 0 R", the describing radiusbars E S and H P will have closed completely, and main radiusbar O R and describing radiusbars E P" and H P will be in the same straight line, while the toolbar T B will be at right angles to the main radius-bar G R.

In this position the main radius-bar OR moves on in the same direction toward the'position 0 R while the slide S becomes the pivoted point P and the former pivoted junction of the tool-bar T B and describing radius-bar H P becomes the slide S At the same instant that this'exchange of the control of the toolbar T B is made between the two radius-bars E? P and H P the direction of angular motion'of the describing radiusbars is reversed, as shown by the arrows, and the tool-bar T B" andtool-point under P are forced to move in an epicycloidal curve by the pivoted point P, and the shank of the tool-in line with the..tool bar is held in a normal position, P 13, to the epicycloid P P by means of the sliding end S of the describing-bar A S.

For the sake of clearness an outline of a i actuated by a feed taken 'off the first-rnotion= shaft Z at Y. The velocity ratio of these two feeds for the tangent-screws X and X X is so proportioned by intermediate gearing that a change-wheel, F, Figs. 2, 3, and 4,,having the same number of teeth as a straight flanked pinion in the basic system used, and another change-wheel, F, Figs. 2, 3, and 4, having the same number of teeth for which the cutter is being made, will produce the proper relative angles of main radius-bar and.

the two describing-bars, and consequently true epi and hypo cycloidal curves.

If for any reason it is not convenient or possible to adjust the feeds as stated, the proportiouality of the angles may be preserved by multiplying or dividing the numbers of.

the teeth of the changewheels F and F by a common factor. Say we set F for fifteen teeth and F for twelve teeth; we can just as correctly set F for five and F for four teeth, or F for thirty and F for twenty-four teeth.

The describing radius-bars NV and V, Fig. 3, are firmly attached by pendants O and Q,

Figs. 3 and 5, to the smaller sectors E' and H,

Figs. 2 and '8, and by means of the set-screws shown they may be adjusted to any required length. The course of the feed-motions from the first-motion shaft Z to the tangent-screws X X X can be traced without diffieulty.

The tool-bar T (shown in detail in Figs. 6

and 7, and also in Figs. 2, 3, and 5) has at its top B a slide, a, Figs. 6 and 7, and is held snugly against the under side of the main radius-bar 0, Figs. 2 and3, by means of another slide in the bottom of-the main radius-bar sliding in a slot, L, Fig. 8, the whole length of the main radius-bar O. The slide in the main radius-bar'O is adjustable, and is fixed in place by means of a set-screw, 2, Fig. 3. A downwardly-extending arm, K, from tool-bar T grips at its bottom a tool-post, J, which firmly holds in exact parallelism with the top, B of the tool-baratool, I. The point P'of the tool is exactly under the center of the tool-bar. Inside of the toolbar T are two slides, b c, Fig. 7, which form part of the pivots S and S Both of these slides can move outward from the fixed stop-pin d, which passes through the toolbar.

When the slides are against the stop d, the pivots S and S are exactly under the center of the bar T. In these slides b c' are two bolt-holes, f and e, to receive the bolts g and h, Fig. 6. These bolts are connected by a lat'ch-bar,j, pivoted at k. The coiled spring Z continually presses against the latch-bar j, and tends to lift the bolt h out of the hole 6 and to push the bolt 9 into the hole f in the slide 1). The latch m is used to hold thelatchbarj against the pressure of the springl when desired. then the bolt h is pressed home in the bolt-hole e, the slideebecom'es-a solid part of the tool-bar T. Therefore S becomes a fixed pivot, and S a sliding pivot. WVhen the bolt 9 is home,the reverse is true,and S isa sliding pivot in the tool-bar, and'S is a fixed pivot. Both of these bolts cannot be home at the same time. lVhen, however, the holef in the slideb comes underneath the hole in the side of the tool-bar in which the bolt g rests, the spring Z will send thebolt g home'an'd release the slide 6. Until hole f comes underneath bolt 9 the spring Z cannot act. The pivots S and S are grasped by the radius-bars NV and V, Fig. 3. Referring to Fig.1,we observe thatthis change of a pivot into a slide must occur at the point Pflaud needs only occur once when changing from one curve to the other in shaping one side of the cutter. lVhen the radius-bar is in the position T B, S has moved a long distance from the stop-pin d, Fig. 7', and therefore the bolt-holef is not under the bolt g, but the bolt end presses on the surface of the slide 1), which is underneath.

In the progress of the tool-barT B toward the position T B Fig. 1, S continually approaches P", at which point the bolt 9, Fig. 5, shoots smartly heme, andthe slide b becomes the pivot S, while the former pivot S becomes is changed to a slide, as explained above, the

'direction of the angular motion of the describ ing radius-bars W and V, Fig. 3, must be reversed, as shown by the arrows in Fig. 1.

On the latch-barj, Fig. 6, is a pin, 12, projecting vertically downward a sufficient distance to strike a pin, 0, on an adjustable lug, q, Figs. 3 and 6, which is adjusted on a re versing-rod, 19. At the sameinstant when, by, reason of the conjoined action of the slide b, Fig. 7, and the spring Z, Fig. 6, the boltg is and 3, from the lower to the upper of a pair of miter-gears, forming a spool, '1", which is constantly drivenin the same direction by a train of gears from the first-motion shaft Z at Y. The miter-gear M, is at the end of a springshaft', 15, which gives it a constant tendency to leave the lower gear of the spool 7" and to engage the upper gear of this spool. These upper and lower gears are fixed. upon the same. shaft and turntogether, and when gear M engages with the upper gear its motion is re-. versed.

The tendency of gear M ,to engage the upper gear is resisted by a steel spring, S, Fig. 3, adjusted to yield to the smart stroke of the pin it, Figs. 3 and 6, upon the pin 0 by means of a connecting linkage, 1 2 3, Fig. 3. The centers of the small sectors Eand H, which control the angular motion of the describing radius-bars W and E, are adjusted inside of the main radius'bar Oto any radius by means ofthe scales to on each side. The tool-bar T is adjusted midway between the centers of the sectors E and'H and w and 1 Figs. 3, 5, and 8 are adj usting-screws for the centers of the sectors E and H. j

m, Fig. 4:, is a scale to'enable the setting over of the main radius-bar a proportionaldistance to the half thickness of the cutter D, Fig. 1,

sent home, the pin n, Figs. 3 and 6, strikes the pin 0 and throws miter gear M, Figs. 2

at the pitch-line of the wheel for which the main radius-bar G by means of the scale Y, as

it is bolted to an adjustable surface-plate, Y.

On the first-motion shaft Z is placed a cam, A, which, by means of a slotted reciprocating bar, B, clamped at D to a pendent crank, E, Fig. 5, imparts a reciprocating motion to the mandrel 'N, on which the disk 0, Figs. 11 and 12 to be formed into a cutter, is placed. Any other of the many means of obtaining a reciprocating motion will answer the purpose as well as the one described.

It is obvious that if we give a continuous rotary motion to the blank disk the tool under the control of the mechanism described 11, we will have a cutter of the exact shape on the cutting-edges, but without the necessary clearance at the back, to enable it to cut rapidly and freely. To avoid this serious objection, I have devised an eccentric mandrel. (Shown in Figs. 9, 10, 11, and 12.)

Assuming the cutter G to be notched, as shown in Fig. 11, astationary spring-pawl, G, engages the teeth and prevents the rotation of the cutter 0 toward this pawl, but permits rotation in the opposite direction, while a reciprocating pawl, H, attached to the mandrel N forces the cutter to turn through the arc of one tooth foreach complete reciprocation. It, now, instead of placing the' cutter concentrically with the mandrel N, we place it on an eccentric mandrel, K, the cutter still has a rotary motion, and is thrown slightly forward at each oscillation oftheswinging crank E, Fig. 5, thus enabling the necessary clearance for the teeth of the cutter. Itthe eccentric mandrel Kis placed below the center of the mandrel N,

the cutter will be drawn backward as well as' rotated at each oscillation ofthe crank E, Fig. 5. The pawl G catches the next tooth, and the cutter must turn on its mandrel a little in re turning to its original position. The amount of eccentricity ofthe two mandrels divided by the radius of the cutter being cut gives the tangent of the angle of clearance or angle of relief of the cutting-edges of the cutter. In order to enable this eccentricity to be varied at will, and also to avoid using the teeth of the cutters as ratchets, l have devised the false eccentric mandrel shown in Figs. 9 and 10. N is the stationary or true mandrel. L is a screw, which adjusts a slide having attached to it the eccentric mandrel K and thespringpawl H. G is a spring-pawl attached to the frame-work supporting the mandrel N. K is the false mandrel, consisting of a ratchetwheel,'Q, and a'cannon, Q, to which the cutter to be formed is keyed. Its mode of action is exactly similar to that described in Figs. 11 and 12 for the cutter 0 alone.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. The combination of the tool-bar T, radius-.

bars XV and V, slides b and c, pivoted at S and S, bolts 9 and h, striking-pin n, reversing-rod .1) l 2 3, tool-post J, and the pivoted slide a,

and mechanism, as described, for driving them and for reversing the motion of the machine, all substantially as set forth.

2. The combination of mandrelN, eccentric mandrel K, cutter O, "stationary pawl G, and

actuating-pawl H, substantially as and for the purposes set forth.

3. The combination of mandrel N, adjusting'serew L, adjustable eccentric false mandrel K, actuating-pawl H, stationary pawl G, and the false mandrel Q, Q, all arranged and opcrating substantially as and for the purposes 

